This invention relates to cellular communications and, in particular, to a signal translating repeater that enables a terrestrial (ground-based) mobile subscriber station to provide wireless telecommunication services in both the terrestrial (ground-based) and non-terrestrial regions.
It is a problem in the field of cellular mobile telecommunication services to provide customers with high quality communication services in a unified manner via a wireless communication medium. Existing cellular mobile telecommunication systems serve terrestrial (termed ground-based herein) mobile subscriber stations, but this service was traditionally not extensible to non-terrestrial mobile subscriber stations due to signal interference problems between ground-based and non-terrestrial mobile subscriber stations. The above-noted U.S. Patents disclose a non-terrestrial mobile telecommunication system and a mobile subscriber station operable in such a system, which provides subscribers with cellular mobile telecommunication services in the non-terrestrial region. However, the mobile subscriber stations used in the ground-based cellular mobile telecommunication system and the mobile subscriber stations used in the non-terrestrial cellular mobile telecommunication system are traditionally architect to operate in only their associated cellular mobile telecommunication system.
Thus, the existing mobile subscriber stations are incapable of being used both in ground-based cellular mobile telecommunication systems and non-terrestrial cellular mobile telecommunication systems. Therefore, subscribers must presently use one mobile subscriber station for the ground-based cellular mobile telecommunication system and another mobile subscriber station for the non-terrestrial cellular mobile telecommunication system. Each of these mobile subscriber stations has an assigned telephone number and the communication services provided to the subscriber are therefore disjunct.
The mobile subscriber station described in the above-noted U.S. patent application Ser. No.: 09/379,825, titled Ubiquitous Subscriber Station, provides wireless telecommunication services in both the terrestrial (ground-based) and non-terrestrial regions. This unique mobile subscriber station enables the subscriber to receive wireless cellular mobile telecommunication services in a unified manner in both the terrestrial (ground-based) and non-terrestrial regions.
However, for subscribers equipped with a traditional ground-based mobile subscriber station, there is no provision for receiving cellular communication services in an aircraft.
The above described problems are solved and a technical advance achieved in the field by the signal translating repeater, located in an aircraft, that enables a traditional ground-based mobile subscriber station to provide wireless telecommunication services in both the terrestrial (ground-based) and non-terrestrial regions. The signal translating repeater extends the usage of existing cellular mobile telecommunication frequencies allocated for ground-based cellular communications to non-terrestrial cellular communications in a manner that avoids the possibility of signal interference between the ground-based and non-terrestrial mobile subscriber stations. In particular, the signal translating repeater automatically transitions between the communications paradigm used by the ground-based mobile subscriber station and the communications paradigm used in non-terrestrial cellular communications. The subscriber therefore can use their ground-based mobile subscriber station in all locations for uninterrupted wireless communications services, either using one telephone number for all locations, or by having a telephone number that is assigned for ground-based wireless communications services and another telephone number that is assigned for non-terrestrial wireless communications services.
The existing ground-based cell site transmitter/receiver antenna installations can be used to serve non-terrestrial mobile subscriber stations by the addition of non-terrestrial antenna elements. These non-terrestrial antenna elements create an antenna pattern which is insensitive to the reception of ground-originating or ground reflected signals and which antenna pattern is transmissive only in a skyward direction. In addition, there exist a number of signal characteristics that can be used to implement a non-interfering signal space. For example, the polarization of the signals produced by the non-terrestrial antenna elements can be a polarization that is different than and preferably substantially orthogonal to the polarization of the ground-based cellular radio signals, such as a horizontal polarization, to thereby minimize the possibility of interference with the vertically polarized ground-based cellular radio signals. Furthermore, the control signals exchanged between the non-terrestrial mobile subscriber stations and the non-terrestrial cell site controller are architected to avoid the possibility of interference with ground-based cell site transmitter-receiver pairs. In particular, the control channels used for the non-terrestrial mobile subscriber stations are selected such that the control signals transmitted in these channels are unrecognizable to the ground-based mobile subscriber stations and ground-based cell site transmitter-receiver pairs so that even if broadcasts from a non-terrestrial mobile subscriber station reach a ground-based mobile subscriber station or cell site transmitter-receiver pair they cannot be interpreted and are rejected out of hand. Optionally, the non-terrestrial system can switch uplink and downlink frequencies to be the opposite of ground-based mobile subscriber station pattern. In this manner, non-terrestrial cells can be created in the region of space adjacent to and overlying the existing ground-based cells and the existing cellular communication frequencies allocated for ground-based cellular telecommunications can be reused for non-terrestrial cellular telecommunications without the possibility of interaction between the existing ground-based cellular mobile telecommunication system and the non-terrestrial mobile subscriber stations. To the mobile telecommunication switching office, the non-terrestrial cells all operate in harmony with the existing ground-based cell sites with no discernible differentiation among cells or stations, whether ground-based or non-terrestrial in nature.
The present signal translating repeater is located in an aircraft and provides service to mobile subscriber stations that are located in the aircraft, using the ground-based cellular communication paradigm. The present signal translating repeater converts these ground-based cellular communication signals into signals pursuant to the non-terrestrial cellular telecommunication format and transmits these signals to the non-terrestrial cell site(s) presently serving the aircraft. In this manner, the subscribers in the aircraft can use their existing ground-based mobile subscriber stations in a manner that is consistent with use in communicating with the ground-based cell sites, while the aircraft communicates with the non-terrestrial cell site(s) presently serving the aircraft in a manner that is consistent with non-terrestrial mobile subscriber stations.
In this manner, the signal translating repeater automatically transitions between the communications paradigm used in ground-based mobile subscriber stations and the communications paradigm used in non-terrestrial cellular communications.